Evaporating apparatus



Allg. l5, J' GQLDlNG EVAPORATING APPARATUS Filed July 17, 19151 2 Sheets-Sheet 1 /lV VE/Y TOR do h n Gold l n g .BY MM5/M Arme/ffy@ Allg. l5, J. GQLD|NG EVAPORATING APPARATUS Filed July 17, 1931 2 Sheets-Sheet 2 .//VI/E/VTOR dol-m Golding Patented Aug. 15, 1933 PATENT OFFICE EVAPORATING APPARATUS John Golding, Shinfield, England Application July 17, 1931, Serial No. 551,363, and inGreat Britain August 1, 1930 6 Claims.

This invention has reference to evaporating apparatus of the kind in which the evaporation of a fluid substance is effected at substantially atmospheric pressure by the use of heated drying rolls, and apparatus according to the invention is particularly applicable for use in the treatment of milk and Whey.

United States Patent Specification No. 1,604,036 describes apparatus of this kind in which the 0 heated vapour rising from the drying rolls is utilized for pre-heating and pre-evaporating liquid subsequently applied to the rolls, the apparatus comprising a pre-heating trough largely enclosed by evaporating sheets arranged above the rolls, a hood spaced from the outer surfaces of the evaporating sheets and means for inducing a counter current of air to pass over the liquid upon the evaporating sheets.

Milk, whey, other diary products and many other substances are liable to deteriorate rapidly and the chief objects of the present invention are to make provision whereby the apparatus may be kept thoroughly clean and to simplify the apparatus in order to increase cleanliness in operation, and to reduce the costs of construction and working. Another important object is to permit liquid to be pre-heated and evaporated Without passing to the rolls, and generally to permit variation in the processes of treatment and resultant product or products.

Further objects advantages and features of the invention will be apparent to those versed in the art fromthe following description and the accompanying drawings, and be more particularly pointed out in the appended claims.

According to one feature of the present inventionrthe lower portions of the evaporating sheets are made detachable to facilitate access to the rolls, and these detachable portions may be formed with gutters and vweirs at the bottom whereby in conjunction with suitable conduits for drawing off some or all of the liquid passing over the sheets the rate of iiow on to the sheets can be increased suiliciently to ensure a complete nlm of liquid on the sheets without supplying an excess of liquid to the rolls. Each lower portion may be made to hook on to the upper portion of an evaporating sheet and to extend at an angle thereto.

Another feature of the` invention may be said to consist in making the hood readily removable or providing it with hinged doors or iiaps, whereby ready access can bel had to the pre-heater and evaporating sheets for cleaning and for spreading the lm evenly over' the sheets at the commencement of an operation. The upper port 'tions of the evaporating sheets and the hood walls may be vertically disposed, and means may be provided for inducing a current of air to pass in counter current or otherwise over the liquid flowing down the sheets.

It may also be mentioned that it has now been found that the pre-heating is of rather secondary importance to the second evaporation or concentration eiiect obtained, and that it is not neces- 6 sary for the dimensions of the pre-heater to be very great, whilst in order to obtain an even and unbroken lrn on the evaporating sheets, top weirs having aiairly wide bend i. e. without a sharp ridge, are preferable.

Furthermore the heated vapour rising from .75. For

Weirs at the top connecting the evaporating sheets to the trough such a perforated baille plate may be disposed some little distance from the top and may also serve to maintainrthe relative positions of sheets and trough. The exhaust conduit may be connected to a space between the sheets and trough above the baiile plate, by a hollow T-shaped member forming a kind of transverse bridge near the top of the trough.; there may be no orifices in the baiile plate beneath the bridge whilst oriiices increasing progressively in size according to their distance from the bridge may be formed practically all around the trough in the remaining portions of the baffle plate. vapour could be obtained by a slot or slots of progressively increasing size, the result sought being to draw the hot vapour as evenly as possible over all the surfaces presented by the preheater trough and inner surfaces of the evaporating sheets. Other suitable baies or `iins may of course be utilized to assist the transfer of heat from the hot vapour to the trough and/ or sheets, and/or to stiften them.

In` order that the invention may be clearly 1 understood and' readily carried into effect the same will now be described with reference to the accompanying diagrammatic drawings, in Which:- 1

Fig. 1 is a side elevation, parts being broken Obviously a similar result on the flow of rolls which may be of the known steam heated type suitably mounted, v2 the lower portions of` evaporating sheets 3 which are shown integral with a pre-heater trough 4 arranged above'the V-shaped space between the rolls 1. f Y

As shown the lower portions 2 of the evaporating sheets are bent over at the top at 5 to fit into grooves or channels 6 formed or provided near the lower edges of the sheets 3, and if the two lower portions 2 be separate they may be hooked into place, in which event the bent portions 5 are preferably slid endwise into the grooves 6 by which they are suspended. Hoods for deflecting steam from beneath the rolls into the vapour space may be mounted at the ends of the machine. The gutters at the bottom of the evaporating sheets are indicated at 7, and 8 are the weirs over which liquid may flow` onto the rolls when not all drawn off by conduits 9 furnished With regulable valves 10; it will be noted that where the weirs project beyond the rolls l they are raised as indicated at 1l, and. with end plates 12 waste of liquid is thus avoided. It is desirable to collect and remove water condensed on the portions 2 by means of appropriate gutters such as 13 adapted to discharge in any appropriate manner.

As shown the hood 14 forming a vapour space 15 around the evaporating sheets 3, is suspended by cables 16 and may be counterpoised so that it is readily removable for the purposes above mentioned by being raised substantially vertically.

The hood 14 is formed or providedat the top withI an `exhaust conduit 1'74 adapted to be detachably connected in any suitable manner with a fan conduit or casing 18, so that air and vapour can be drawn from the vapour space 15 through suitable ports 19 that may be adjustable in size thus drawing air upwards from the bottom'between the hood 14 and the exterior surfaces of the evaporating sheets 3 down which liquid flows. Steam also is drawn from the steam or vapour space 3 by the fan via a suitable conduit 20 removably connected to a hollow T-shaped member 21 forming a transverse bridge near the top of the trough 4.

Curved weirs 22 are shown connecting the evaporating sheets 3 with the trough 4 so that liquid may flow evenly from the trough. onto the sheets thereabout, rand some little distance from the top is a baffle plate 23 having orifices 24 progressively increasing in size or number according to their distance from the bridge 21 with a View to drawing the hot vapour rising from the rolls 1 evenly over all the surfaces presented thereto by the trough 4 Yand evaporating sheets 3.

The single unit formed by the trough 4 and sheets 3 is shown removably supported by adjustable bearers 24 mounted on suitable beams .25 or the like at the ends of the apparatus suitable brackets 26 secured to sheets. 3 being adapted ly the same height by adjusting the unit so that its top is level. It will be seen that these bearers may also support combined gutters and baffles 27 and 28 for collecting condensed water and for directing the steam onto the sheets 3. The water collected in the upper gutter 27 is led into the lower gutter 28 by the pipe 29 and therefrom by any suitable conduit (not shown). This unit is preferably made of copper for good heat conduction and tinned to avoid corrosion as are other parts having similar requirements.

Other gutters for collecting condensed water that runs down the sheets 3 are shown at 30, and all the water collected in the various gutters may be led into a tank at the end of the apparatus from which it may be drained by a pipe 31. Obviously gutters for this purpose may be variously constructed and arranged.

Liquid, such as whey, is introduced into the trough 4 at the bottom by means of a pipe 32. This pipe may be furnished with a two-way cock 33 from which a further pipe 34 leads to a bulk storage or supply tank, while the pipe 35 may be utilized for draining and emptying the trough 4 into the gutter 7 at the close of the dayls work also when the trough is washed out after use. The liquid displaced upwards by that fed in overflows the weirs 22 onto the evaporating sheets 3, forming a substantially uniform cascade, so that a substantially unbroken and uniform film of liquid flows down the sheets to vthe bottom gutters '7, from which some of the liquid may be drawn by the conduits 9, while some may flow over the weirs 3 onto the rolls. Gutters 3 around eachend of the sheets 3 liquid flowing down the end surfaces onto the lower portions 2 and thus into the gutters 7. These weirs 8 and any distributor for supplying liquid directly onto the rolls 1 are preferably so arranged or disposed'that liquid for treatment or further treatment may flow onto the drying rolls 1 adjacent the adjustable doctor blades 36 (of known form and supported in any usual manner) scraping olf the film of treated substance therefrom, the liquid being preferably applied at or near the khighest point or crown of the rolls, but on the side of crown remote from the doctor, so that it remains thereon for the greater part of a revolution.

It will be appreciated that apparatus as hereinbefore described lends itself^ to many methods of use. For example suppose milk and whey are to be treated, the milk may be supplied directly to the V-shaped space between the rolls l enclosed by the usual adjustable end plates, or onto the crown ofl one of the rolls by a suitable distributor (not shown) and the whey may be passed through the pre-heater 4 and over the evaporating sheets 3, 2 thus undergoing concentration and pasteurization and back to a bulk or storage tank, or if desired, some of the whey may be returned to the bulk tank from one or b'oth of the gutters 7 whilst some passes over one or both of the bottom weirs 8 on to the drying rolls l where it becomes mixed with the milk undergoing treatment. Since the amount of whey passing to the rolls will be substantially less than that passed over the top weirs 22, particularly when a large proportion is being returned to the bulk tank by the conduits 9, it may in some cases be desirable to make special provision for applying an even nlm of whey to the rolls, such means might for exampleV comprise auxiliary feed rollers (not shown) adapted to facilitate transfer of the whey from the bottom gutters to the rolls.

Suitable pumps, fans, conduits, tanks and recollect and divert the Y ceptacles of any-ordinary or appropriate con` struction are of course provided in practice, the conduits or pipes being furnished with suitable control taps or the like; some of such devices the construction or arrangement or" which would be obvious to those versed in the art have not been illustrated in the accompanying drawings to avoid complicating same and as they may be said to form no part of the present invention. Sirnilarly and for reasons of space the pulleys or the like over which the hood supporting cables may pass to a counterweight or counterweights are not illustrated; moreover where suspension cables as illustrated are employed they may of course be secured at their other ends to a suitably secured winch or winding drum.

It will also be understood that the drawings are diagrammatic and by way oi illustration, and that various changes or modifications in the apparatus may be made within the scope of the appended claims.

I clairnzl. In evaporating apparatus comprising heat-` ed drying rolls, a pre-heating trough and evaporating sheets through and over which respectively liquid under treatment flows, said trough and evaporating sheets being superimposed above said rolls, a hood enclosing said sheets, means adapted to induce a current of air to pass over the liquid on said sheets and means to drawwoiF vapour, detachable lower portions for said evaporating sheets formed with gutters at the 'bottoni disposed to receive said liquid under treatment, said gutters having weirs over which liquid can iiow onto said rolls and draw-off conduits communieating with said gutters.

2. In evaporating apparatus comprising heated drying rolls, a pre-heating trough and evaporating sheets through and over which respectively liquid under treatment iiows, said trough and evaporating sheets being superimposed above said rolls, a hood enclosing said sheets, means adapted to induce a current oi air to pass over the liquid on said sheetsand means to draw oli? vapour, gutters with weirs formed at the lowerv extremities of said evaporating sheets, drawoi devices associated with said gutters and regulable means applied to said draw-oilC devices regulating the amount of liquid under treatment drawn off from the gutters and therefore not passing over the weirs onto the rolls.

3. In evaporating apparatus comprising heated drying rolls, a pre-heating trough and evaporating sheets through and over which respectively liquid under treatment iiows, said trough and said sheets being superimposed above said rolls, gutters with weirs at the lower extremities of said sheets and adjacent said rolls, said gutters receiving the liquid under treatment, a hood substantially enclosing said sheets, means inducing a current of air to pass evenly over said sheets and drawing on. vapour within the hood, and means drawing off vapour from the space within the evaporating sheets and previously directing said Vapour over substantially all exterior surfaces of said trough.

4. Apparatus as claimed in claim 3, in which the last mentioned means comprises a baiile plate formed with orices progressively increasing in area according to their distance from an exhaust conduit, said exhaust conduit comprising a hollow transverse bridge over said trough.

5. Evaporating apparatus comprising heated drying rolls, a pre-heating trough and evaporating sheets enclosing said trough, the inner surfaces of said sheets being spaced from the outer surfaces of said trough, weirs mechanically connecting said trough and sheets, gutters at the lower external extremities of evaporating sheets and adjacent said rolls, conduits leading from said gutters, a readily removable hood open at the bottom adapted to enclose the major portion of said evaporating sheets but spaced therefrom, an exhaust conduit communicating with the interior of said hood and an exhaust conduit communicating with the space between said trough and evaporating sheets.

6. In evaporating apparatus comprising heated drying rolls, a preheating trough and evaporating sheets through and over which respectively liquid under treatment flows, said trough and evaporating sheets being superimposed above said rolls to utilize heated vapour arising from the rolls, al hood enclosing said sheets, means adapted to induce a current of air to pass over the liquid on said sheets and means to draw 01T vapour, detachable lower portions for said evaporating sheets, said sheets having channels adjacent their lower extremities and said lower portions being bent over at their tops to engage in said channels for support and also so bent as to extend at an angle to said sheets respectively when supported in operative position above said rolls, the detachable lower portions of said evaporating sheets being formed with gutters at the bottom disposed to receive said liquid under treatment, said gutters having weirs over which liquid can flow onto said rolls and draw-off conduits communicating with said gutters.

JOHN GOLDING. 

